Bioremediation of contaminants by plants

https://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet

Introduction

Whenever you see oil rigs or pollutants cover the soil, you must be pondering how much of a deal contaminants are to the environment. To put it into perspective, oil spills that come from industrial activities such as petroleum engineering and waste disposal is a problematic global issue for the environment. The conventional methods to clean up oil spills often involve both physical and chemical processes that might do more damage toward the coastal environment than the oil spill itself (Ndimele, P. E., 2010). Unfortunately, there is increasing demand to develop more eco-friendly techniques that will can clean up environmental contaminants and also restore the aquatic ecosystem back to a healthy state (Ndimele, P. E., 2010). How and why phytoremediation is a promising method of bioremediation will be explored.

Why contaminants are a big concern

Coastal ecosystems are still influenced by human interaction with the environment and the types of resources that they utilize on a daily basis (Marcovecchio, Jorge E., et al., 1994). The estimated amount of crude oil released into the water is between 1.7 to 8.8 million metric tons and more than 90% is related to human use, such as waste disposal (Ndimele, P. E., 2010). High amounts of pollutants such as sewage in coastal areas can have a negative impact on organisms by depleting the amount of oxygen and asphyxiate underwater life (Matthiessen, Peter, 2002). Currently, there are land based methods to help remediate the contaminants in the coast, and one of them is phytoremediation.

What is Phytoremediation

Phytoremediation is the removal of contaminants through the use of plants or other microbes. The removal of pollutants with plants can be inexpensive and but may take more time than the conventional methods because it is a natural process. Phytoremediation is a complex string of mechanisms that remove contaminants, and they consist of: (1) Phytodegradation (organic contaminants are degraded by plants), (2) phytovolatilization (take up contaminants and release them into air) (Limmer M. et al., 2016), (3) phytometabolism (incorporate nutrients contaminants into biomass), (4) phytoextraction (extracts and stores contaminants into plant tissue), (5) phytostabilization (plants can prevent the contaminant’s mobility), and (6) phytohydraulics (can change groundwater hydrology such as water uptake through transpiration). Phytoremediation can help degrade contaminants such as petroleum hydrocarbon, and they can influence nearby microbes to metabolize contaminants in the rhizosphere with aromatic compounds. Habitats that were damaged by contaminants can even be restored by phytoremediation due to their influence on vegetation and enhancing the reforestation process (Lin, Qianxin et al., 2009).

Figure 1. As shown in this image, phytoremediation has several stages in removing contaminants. It also provides a few environmental benefits such as reforestation. Phytoremediation can directly influence microbes such as fungi and algae (De-Bashan, Luz E., 2012).

Problems with phytoremediation

Bioremediation methods by using plants have proven to be useful for contaminant removal in soils. But the main concern that arises from phytoremediation is that because phytoremediation is still a new technology, the actual processes of contaminant removal by plants is still not fully understood. Other concerns in using phytoremediation with plants is that there are not very plants capable of taking up PCBs, and thus more research needs to be. Plants that are in symbiotic associations with mycorrhizal fungi need to also be taken into consideration when it comes to phytoremediation (Kumar, Vankayalapati Vijaya, 2017). While plants can take up contaminants, there are certain pollutants that cannot be degraded such as heavy metals and they will keep on accumulating in the plant tissue.

Conclusion

Contamination in coastal areas poses a serious threat to both the environment and to other organisms. Phytoremediation is an inexpensive, but efficient form of bioremediation and it can undergo several stages to degrade contaminants into less . So if you want to help clean out contaminants at the coast with environmentally friendly methods, plant some trees nearby. But most importantly, spread the word about this recent bioremediation and why using plants is important for dealing with pollutants. If these organisms can put in so much effort to remove hazardous material from the soil, then we should help them out too.

References Cited

De-Bashan, Luz E., Juan-Pablo Hernandez, and Yoav Bashan. “The potential contribution of plant growth-promoting bacteria to reduce environmental degradation—A comprehensive evaluation.” Applied Soil Ecology 61 (2012): 171-189.

Kumar, Vankayalapati Vijaya. “Mycoremediation: A Step Toward Cleaner Environment.” Mycoremediation and Environmental Sustainability. Springer, Cham, 2017. 171-187.

Limmer, Matt, and Joel Burken. “Phytovolatilization of organic contaminants.” Environmental science & technology 50.13 (2016): 6632-6643.

Lin, Qianxin, and Irving A. Mendelssohn. “Potential of restoration and phytoremediation with Juncus roemerianus for diesel-contaminated coastal wetlands.” Ecological engineering 35.1 (2009): 85-91.

Lin, Qianxin, and Irving A. Mendelssohn. “The combined effects of phytoremediation and biostimulation in enhancing habitat restoration and oil degradation of petroleum contaminated wetlands.” Ecological Engineering 10.3 (1998): 263-274.

Marcovecchio, Jorge E., et al. “Environmental contamination and marine mammals in coastal waters from Argentina: an overview.” Science of the Total Environment 154.2-3 (1994): 141-151.

Matthiessen, Peter, and Robin J. Law. “Contaminants and their effects on estuarine and coastal organisms in the United Kingdom in the late twentieth century.” Environmental Pollution 120.3 (2002): 739-757.

Ndimele, P. E. “A review on the phytoremediation of petroleum hydrocarbon.” Pakistan Journal of Biological Sciences 13.15 (2010): 715.

Yang, Yurong, et al. “The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil.” Scientific reports 6 (2016): 20469.